At the time of his death in 1910, Mark Twain left behind an unedited 5,000-page manuscript of his autobiography with explicit instructions that the work not be made public for at least 100 years. In November, the University of California, Berkeley, will publish the first volume of the writings in what eventually will be a trilogy.

Why the century-long hold on publishing the work?Nobody can say for sure, but Twain might have been worried that his grouchier opinions would hurt his public image. "He had doubts about God," notes Michael Shelden, author of a new account of Twain's final years, Man in White. He also might have wanted to avoid offending friends — the book contains many cruel observations about people Twain knew.

Has anyone seen the material before?Yes, historians and biographers willing to travel to Berkeley have been able to read through the manuscript, and share relevant bits in their own books about Twain. Parts of it were also published as magazine excerpts prior to Twain's death. But University of California editors say that about half the material has never been seen by general audiences before.

Will the book include shocking revelations?A few. For starters, Twain devotes a 400-page section to his "little-known but scandalous relationship with Isabel Van Kleek Lyon, who became his secretary after the death of his wife, Olivia, in 1904," according to Britain's Independent. Lyon even once bought Twain an electric vibrating sex toy — "Um, TMI, Mark," says Dan Fletcher in Time — but the relationship ended badly when Twain said she had "hypnotized" him into giving her control over his estate.

Is the autobiography likely to change how people think about Twain?Maybe — it's certainly contrary to the common perception of him as "a sort of genteel Victorian," says Laura Trombley, author of a book about Lyon called Mark Twain's Other Woman. "In this document he calls [Isabel Van Kleek Lyon] a slut and says she tried to seduce him. It's completely at odds with the impression most people have of him." When the first volume comes out, people will see that Twain didn't spend his final years "basking in the adoration of fans. The autobiography will perhaps show that it wasn't such a happy time. He spent six months of the last year of his life writing a manuscript full of vitriol, saying things that he'd never said about anyone in print before."